1. Field of the Invention
The present invention relates to a dielectric ceramic composition and a ceramic electronic device having a dielectric layer composed of the dielectric ceramic composition.
2. Description of the Related Art
A laminated ceramic capacitor as an example of a ceramic electronic device is widely used as an electronic device which has a small size and exhibits high performance and high reliability, and a number of laminated ceramic capacitors are mounted as an electronic device for motor vehicle.
The laminated ceramic capacitor for mounting on a motor vehicle is essentially required to be adaptable to even a high-temperature and high-voltage environment as well as to have a small size and to exhibit high performance. In recent years, the laminated ceramic capacitor is required to be improved in operation guarantee and reliability in a high-temperature environment of from 125 to 150° C. and at from 16 V to 100 V.
A laminated ceramic capacitor exhibiting high reliability while meeting the X8R characteristics is described in Patent Literature 1. In addition, Patent Literature 1 mentions that a thickness of the dielectric ceramic layer composed of the laminated ceramic capacitor can be thinned to 10 to 15 μm.
In recent years, however, it has been required that the laminated ceramic capacitor is further miniaturized and the dielectric layer is thinned. It has been known that the reliability decreases when the dielectric layer is thinned in association with the miniaturization of the laminated ceramic capacitor as the electric field intensity to the dielectric layer is stronger even though the same voltage is applied.
Patent Literature 1: Japanese Unexamined Patent Publication No. H7-37427